My client accidentally called a paging group and then it put it on hold. Unfortunately, it's not possible to get back the call from the calling phone. The only way to recover the phone is to kill the call in the web interface. Same thing for line info, if you put it on hold, it's not possible to unhold it. But this case is not a big deal because the call hangup by itself. Worst, the phone ring every few second to remember that there is a call on hold and this is very annoying.

Also, if the person who receive the intercom put it on hold, it's not possible to unhold it until the call is dropped by the web interface.

Boot loader: 5.2.8/Release
Firmware Version: 5.2.47/Release

Phone, Aastra 9143i
Firmware Version
Firmware Release Code SIP
Boot Version